The war against narcotics along the U.S.-Mexico border appears to be heating up, with casualties mounting on both sides, and much of the carnage is blamed on drug cartels with links to a clannish family of Mexican drug overlords who control much of that nation’s multibillion-dollar “narco” industry.

Drug-related violence has claimed hundred of lives in cities near both sides of the border in recent years, much of it traced to groups linked with the ultra-violent Sinaloan Cowboys cartel, so dubbed by California authorities in reference to their home state of Sinaloan and their style of dress fancy boots, belt buckles and white hats.

Some authorities in Phoenix, Ariz., blame Mexican drug gangs like the Sinaloans, which they say is the deadliest, for up to 40 percent of the homicides in the metropolitan area in the past two years. The total number is uncertain, they admit, because many victims, most of them Mexican nationals, are unknown to law enforcement, which has had difficulty cracking the gangs.